Typically, anti-counterfeiting media (hereinafter “identification media”) for preventing unauthorized use by counterfeiting/duplication of products are used for securities such as paper currency, stock certificates, gift vouchers and credit cards, and products such as medical goods, food goods, and expensive brand goods
For the securities, the identification medium may be directly printed or transferred.
For the products, a seal or a tag provided with the identification medium is provided.
However, unauthorized securities and products with counterfeited or duplicated identification media have been recently manufactured, and it has been difficult to determine, based only on the presence or absence of the identification media, whether these securities and products are authentic or fake (counterfeit goods, duplicated goods, etc.).
Examples of the above-described identification medium include a diffraction grating and a hologram whose color or pattern is variable according to an observation angle. Moreover, other examples of the identification medium include optically variable inks and pearl pigments whose color or brightness is variable, and application of a microlens.
With a method by comparison with an authentic identification medium, examination by a specialist, etc., it is easily determined whether the anti-counterfeiting medium is authentic or fake. However, for general users, it is difficult to visually perform anti-counterfeiting authenticity determination.
In a case where authenticity determination on the identification medium cannot be visually performed, a special authenticity determination device (see, e.g., Patent Document 1) capable of precisely controlling an observation angle of an imaging device with respect to the identification medium is utilized.
However, special knowledge and special tools are required for handling the above-described authenticity determination device, and for this reason, it is difficult for general users to determine authenticity of the identification medium using such a device.
Meanwhile, particularly in distribution of medical goods, food goods, expensive brand goods, etc., not only authenticity of these products but also product information and product distribution paths have been advertised to general users, and in this manner, an attempt has been made to enhance the value of the products.
In the above-described fields, code information is provided to individual products by a two-dimensional code typified by a so-called bar code or a QR code (registered trademark), or character information such as numbering.
There is a case where guiding to a web site for displaying related information, playing of a lottery, mail delivery, etc. are performed by input or reading of the code information into a mobile terminal or a PC terminal.
For the QR code (registered trademark), it has been proposed that the code is blocked and part of the blocked code is encrypted (see, e.g., Patent Document 2).
However, the above-described code information can be easily duplicated by a copy machine etc. Even when the code is encrypted, if the code information itself is duplicated, it is difficult to perform product authenticity determination from the identification medium merely having the code information.
For this reason, it has been proposed that a portion having a visual authenticity determination function and code information readable by infrared light are combined together as in Patent Document 3.
In the above-described method, it is difficult to duplicate the code information using a copy machine etc., but it is difficult for general users to perform authenticity determination for identification media which seem similar. Moreover, special dedicated equipment is also required for reading the code information.
[Citation List] [Patent Literature] [PTL 1] JP 3865763 B; [PTL 2] JP 2000-148922 A; [PTL 3] WO 2014/148338.